If you want to try out diskeeper, you can get an[older] version of diskeeper lite free.
They have pulled the link from their website a couple years back, but the download link still works:
http://www1.execsoft.com/dklite.exe
I use it on all my windows boxes without problems here. None of the defrag-in-background or scheduling, but it does alert you when it's time via the use of a service.
An excellent piece of freeware, and I can highly recommend it.
And, yes, I have witnessed the fact that if you lose power during a defrag, your data is not harmed...A friendly service guy decided to reset the main breaker to see if that would fix a problem with an electrical outlet...